Pre-draft Only four days after the
2011 BCS National Championship Game, Fairley decided to forgo his final year of eligibility, entering the
2011 NFL draft. He was initially projected to be the first pick in the draft. His measurements at the combine showed him to be 6 feet 3 7/8 inches tall and 291 pounds, somewhat less than his listing of 6–5 and 300 pounds at Auburn. After the NFL Combine, he was projected in the 8–12 range.
Detroit Lions Fairley was selected by the
Detroit Lions in the first round as the 13th pick overall. He signed a 4-year contract with the Lions on July 28, 2011. The contract was for four years and worth $10 million with a $5.7 million signing bonus. In Detroit, he joined All-Pro
Ndamukong Suh on the interior of the Detroit defensive line. Though at times his play was stout, he was troubled by inconsistency. In his
second season in the NFL Fairley recorded 5.5 sacks, 2 forced fumbles, and 26 tackles. However, on December 12, 2012, Fairley was put on the
injured reserve list, ending his season. Fairley's
fourth season had been productive for the most part. However, on October 26, 2014, Fairley sustained a
medial collateral ligament sprain against the
Atlanta Falcons at
Wembley Stadium in
London.
St. Louis Rams On March 13, 2015, Fairley signed a one-year, $5 million contract with the
St. Louis Rams. Fairley played in 15 games for the Rams in 2015 along their defensive line rotation and recorded 29 tackles (18 solo), a split sack, a pass defended, and one fumble recovery. On December 31, Fairley was placed on injured reserve.
New Orleans Saints On March 28, 2016, Fairley signed a one-year, $5 million contract with the
New Orleans Saints. After recording career-highs in tackles and sacks in 2016, Fairley signed a four-year, $30 million contract extension with the Saints during the 2017 off-season. On June 26, 2017, the Saints placed Fairley on the reserve/non-football-illness list regarding a lingering heart condition, ending his 2017 season. On February 5, 2018, Fairley was released by the Saints. ==NFL career statistics==